ECE 198 Lecture Notes - Arithmetic Logic Unit, Codebook, Block Diagram
Document Summary
Ece 198 worksheet 7: digital cell phone calls. In 2007, the fcc stopped requiring cell phone carriers to support analog cell phone calls. While the cell phone carriers trumpeted this change as a critical revolution in the quality of cell phone calls (higher clarity! ), the hidden reality is that digital cell phone calls cost a fraction to transmit. All human speech is produced from a small set of basic sounds. These base sounds are composed of a set of samples. By performing arithmetic operations on these base sounds, we can synthesize any human voice. Consequently, we can reproduce any voice call with a set of base sounds (a codebook) and arithmetic operations (filters). Rather than transmit a recording of your voice (the analog method), digital calls transmit data indicating which base sounds to use and control data for the filter.